Briones Reservoir is an open cut terminal water storage reservoir located in western

Contra Costa County ) of the San Francisco Bay , subdivision_type = Country , subdivision_name = United States , subdivision_type1 = State , subdivision_name1 = California , subdivision_type2 ...

, in the

East Bay The East Bay is the eastern region of the San Francisco Bay Area and includes cities along the eastern shores of the San Francisco Bay and San Pablo Bay. The region has grown to include inland communities in Alameda and Contra Costa countie ...

region of the

San Francisco Bay Area The San Francisco Bay Area, often referred to as simply the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bay estuaries in Northern California. The Bay Area is defined by the Association of Bay Area Go ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

. It is owned and operated by the

East Bay Municipal Utility District East Bay Municipal Utility District (EBMUD), colloquially referred to as "East Bay Mud", is a public utility district which provides water and sewage treatment services for an area of approximately in the eastern side of the San Francisco Bay.S ...

(EBMUD).

Geography

The reservoir is in the

Briones Hills The Briones Hills form a low mountain range in western Contra Costa County, in the East Bay region of the San Francisco Bay Area, California, United States. Geography The hills are in the Southern Inner Coast Ranges group of the California Coas ...

, on the west side of

Briones Regional Park Briones Regional Park is a regional park in the East Bay Regional Park District (EBRPD) system, located in the Briones Hills of central Contra Costa County of the San Francisco Bay Area in California. Geography The park is located in rolling h ...

and northeast of Orinda. It is impounded by Briones Dam, an earthen dam completed in 1964. The

reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

is the largest of EBMUD’s five East Bay terminal reservoirs, with a total capacity of , and it has a total watershed of 8.59 square miles (22 km²). Briones Dam

Water Source

The Briones Reservoir has two sources for its water, one local and one imported. Its watershed of 22 km² includes the Bear Creek drainage. Bear Creek formerly flowed down the valley, which the reservoir partially submerges, and still enters from the eastern section. The major water source into the Briones Reservoir is imported from the Briones Diversion Works near Orinda. It is delivered through the Briones Aqueduct, a 7-foot, 6-inch steel pipe, operated by four pumps that can deliver up to 60 million gallons a day. This is water imported from EDMUD’s biggest water source, the

Mokelumne River The Mokelumne River ( or ; ''Mokelumne'', Miwok for "People of the Fish Net") is a -long river in northern California in the United States. The river flows west from a rugged portion of the central Sierra Nevada (U.S.), Sierra Nevada into the Ce ...

in the

San Joaquin Valley The San Joaquin Valley ( ; es, Valle de San Joaquín) is the area of the Central Valley of the U.S. state of California that lies south of the Sacramento–San Joaquin River Delta and is drained by the San Joaquin River. It comprises seven c ...

. Water then leaves Briones Reservoir and flows to the lower part of the valley and into

San Pablo Reservoir The San Pablo Reservoir is an open cut terminal water storage reservoir owned and operated by the East Bay Municipal Utility District (EBMUD). It is located in the valley of San Pablo Creek, north of Orinda, California, United States, and south of ...

. From there, the water is distributed by a pumping plant in

Kensington Kensington is a district in the Royal Borough of Kensington and Chelsea in the West End of London, West of Central London. The district's commercial heart is Kensington High Street, running on an east–west axis. The north-east is taken up b ...

Recreation

Because the water in the reservoir is mainly for human

potable water Drinking water is water that is used in drink or food preparation; potable water is water that is safe to be used as drinking water. The amount of drinking water required to maintain good health varies, and depends on physical activity level, ag ...

uses, EBMUD is very strict about recreational activities. Fishing, swimming, and wading are not allowed. However, college rowing teams from

Mills College Mills College at Northeastern University is a private college in Oakland, California and part of Northeastern University's global university system. Mills College was founded as the Young Ladies Seminary in 1852 in Benicia, California; it was ...

, UC Berkeley and Saint Mary's College have permission to use the lake under certain rules, such as the inspection of all boats before use on the lake in order to prevent contamination. Two trails, the Bear Creek Trail and the Oursan Trail, together form a 14-mile (23 km) hiking trail loop that circumnavigates the reservoir. The

trailhead A trailhead is the point at which a trail begins, where the trail is often intended for hiking, biking, horseback riding, or off-road vehicles. Modern trailheads often contain rest rooms, maps, sign posts and distribution centers for information ...

is at the Bear Creek Staging Area, which is within

. A Trail Use Permit issued by EBMUD is required for all hikers, which can be obtained online at the EBMUD website for $10. No mountain biking is permitted on the trail. Horseback riding is allowed. Dogs are allowed on the Oursan Trail segment only, and must be leashed.

Geography

Water Source

Recreation

Photos

See also

References

External links